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Statistical forecasting algorithms

On this page we'll show you what Prophecy™ has got to offer in terms of statistical sales forecasting.  Prophecy™ offers much more than statistical sales forecasting.  But, if you are interested in Prophecy's statistical sales forecasting options, this page is for you!

Supported Statistical Forecasting Algorithms in Prophecy.

Prophecy™ supports the following time series forecasting methods:

Linear Regression: A linear regression analysis draws a straight line of best fit through the historical sales.

Exponential Regression :Similar to linear regression, but works with the logarithms of sales, resulting in a ‘bendy’ line.

Holt Winters : An extension of the exponential smoothing method. Consists of an exponentially smoothed component and a trend component. This method is claimed by statisticians to better reflect long term trends than simple exponential smoothing techniques.

Last Yr + YOY% : This method is proprietary to Prophecy and takes the actual sale for each period in the previous year, and increases/reduces it by the latest complete year over year (‘YOY’) percentage. This is a simple method for populating a new year with data, where the peaks and troughs in the forecast can be clearly understood by matching them to the corresponding period in the previous year and it also reflects the most recent year on year trend.

How Prophecy™ Uses Its Statistical Forecasting Engine

Prophecy™ make the sales forecaster fully responsible for their forecasts and statistics is just one tool they can use to help them develop more defensible sales forecasts.  Therefore the 'engine' appears in several places in Prophecy, but the human forecaster is always fully involved in applying or not applying the results.

'Batch mode' statistical forecasting

Batch forecasting is the closest to how other sales forecasting solutions deliver statistical forecasting - i.e. select a batch of product / customer combinations and generate statistical forecasts for them all, via a guided 'Wizard':

Batch mode statistical forecasting wizard in Prophecy ™

The Batch Statistics Wizard has 8 steps, allowing you to automatically exclude outliers, discard forecasts where the test interval MAPE is outside a set limit, reject negative forecasts etc..

 The 'Tournament Mode' option forecasts the most recent <n> periods, using all the remaining history and chooses the method that has the lowest MAPE over the test interval.

'On demand' statistical forecasting

This option lets the forecaster see a statistical forecast for the item at the current cursor position in their Prophecy forecast update and report screen in a separate window.  The window is refreshed in real time for the item at the cursor position as the forecaster navigates from cell to cell in their main Prophecy forecasting report screen.

Forecasters can compare their current forecast with the statistical forecast and decide to replace some or all of the current forecasts with the statistical forecasts.

'On demand' statistical forecasting wizard in Prophecy ™

The 'Forecast Wizard'

This option lets you select a range of forecast cells in any Prophecy™ forecasting report and fill them with results from the statistical forecasting engine.  You can choose from the statistical forecasting methods described earlier, as well as:

  • Moving Annual Average
  • Running rate over previous 3, 6 or 9 periods
  • Previous month plus, minus, times or divided by a number
  • Same period last year plus, minus, times or divided by a number
Forecast Wizard in Prophecy ™

The forecaster simply clicks the cell containing their chosen method.  The 'Paste Cell' or 'Paste All' buttons push the forecasts into the Prophecy™ forecasting report.  (The cell shaded in green on the Wizard is the 'winner' of the tournament of methods - i.e. the algorithm that forecasts recent periods the most accurately.)

The Prophecy 'Advisor'

The Prophecy™ Advisor is an 'expert system' that runs in the background and constantly evaluates your forecasts, as you enter them.  It pops up a message if it detects that a forecast has been made which is outside previous historical experience.

Note that, (a) the automated appearance of the 'Advisor' can be suppressed if desired and (b) forecasting outside previous history is not necessarily wrong. Although it is surely a good thing to be warned of it!

Prophecy ™ Advisor Warning message

Sales Forecast Accuracy Analysis

Prophecy's Sales Forecasting Accuracy Report uses the statistics engine to compare the official forecast with the forecast that the statistical engine would have used.  This lets forecasters easily quantify the 'added value' of their forecasts versus the statistical engine.

Human forecasts versus statistical forecasts in Prophecy ™

Summary

As you can see, Prophecy™ strives to imaginatively use statistical forecasting as a forecasting aid for the forecaster and not as a replacement.  It is not a 'black box' and the forecaster is always in control of their forecasts.